Proteins have been used in wide variety of products to perform a variety of functions and to impart desired characteristics to product formulations. Proteins have also been used to provide films and substrates which confer specifically desirable properties related to function, appearance, texture, and durability to many products in home-care, health-care, and many other consumer and industrial market segments.
However, natural proteins may not exhibit all desired characteristics and functions when used in product formulations. For example, natural silk proteins may impart durability but may also form tight, hard fibers that are not suitable for film formation. Many natural proteins have a low isoelectric point, and the low isoelectric point reduces the affinity of the protein for the negatively charged substrates. This is particularly problematic in personal care formulations where target substrates such as skin and hair typically are negatively charged, and proteins may accumulate on hair or skin over time. Additionally, more than one protein may be needed to impart all desired characteristics to a given formulation, and the necessity of using more than one protein may increase the cost and production time for a given product. Proteins may be chemically modified or quaternized in order to make them more suitable for inclusion in desired applications. However, even chemically modified proteins may not have all desired characteristics.
Active agents such as fragrances, dyes, tints, UV actives, sunscreens, lanolin, vitamins, bleaches, thickening agents, silicones, proteins/peptides, enzymes, antimicrobials and preservatives have been added to various products to impart a number of desired characteristics or functions. For example, specifically in personal care products, silicones have been used to provide protection and moisturization. Amino functional silicones may polymerize in air and provide improved compatibility, electrostatic reduction, and soft touch for hair. Silicones may also provide lubrication and gloss for hair, skin, or nails. Fragrances have been used as finishing ingredients to impart a desired odor. Radioprotective agents have been employed in a variety of products directed to UV-sensitive applications including personal care, clothing and home care products.
Many active agents lose viability over time and may not exhibit good bulking activity or good film forming characteristics. Many active agents may be insoluble in water, and thus the active agents may have to be applied as aqueous emulsions. For instance, proteins and peptides may be desirable active agents, particularly for protein-based applications, but incorporation into formulations may be problematic due to their generally high levels of hydrophobicity, and incorporation into material substrates may subject them to laundering or other cleaning effects, causing loss of the active agent as well as functional efficacy, over time. Thus, the active agents may not be suitable for all applications, and their inclusion in certain applications may be difficult due to their interactive properties such as hydrophobicity, and/or binding and structural limitations.
Thus, there remains a need in the art for preparations that have desired characteristics of proteins and active agents, and for methods of deliberately tailoring the proteins and active agents to the unique product and delivery demands of specific applications. There also remains a need in the art for products incorporating such preparations.